1. Field of the Invention
The present invention relates to an organic light emitting diode and a method of fabricating the same.
2. Description of the Related Art
An organic light emitting diode, utilized as a self-emissive display, is thin and light, and has simple components and manufacturing processes. It can produce a high-quality image with a wide viewing angle, it can display ideal moving images and high color purity, and it has low power consumption and low driving voltage characteristics suitable for mobile displays.
A conventional organic light emitting diode includes a pixel electrode, an emission layer (EML) formed on the pixel electrode, and an opposite electrode formed on the EML.
In order to effectively perform injection or transport of electrons from the opposite electrode to the EML, one or a plurality of layers such as an electron transport layer (ETL) or electron injection layer (EIL) may be further interposed between the EML and the opposite electrode.
In the structure of the conventional organic light emitting diode, layers interposed between the opposite electrode and the EML are generally disposed such that the absolute value of the lowest unoccupied molecular orbital (LUMO) energy level decreases in steps from the opposite electrode to the EML. However, in the aforementioned structure, even under a low voltage (e.g., about 4V or less) for displaying black, a current density of about 0.1 mA is maintained, resulting in a certain degree of luminous efficiency. Therefore, an element may dimly emit light when the black color is represented, which degrades the quality of the organic light emitting diode by lowering contrast and misrepresenting black in a dark place.